1. Field of the Invention
This invention relates to a method for the treatment of a monolithic or laminated glass pane for the bonding of a peripheral profile and, more precisely, of a moulded-on peripheral profile (or encapsulating seal). This treatment may also be applied for the bonding, onto a pane, of a profile deposited by extrusion.
2. Description of the Related Art
This type of profile is generally manufactured and mounted on the pane by the pane manufacturer. The panes are then delivered, notably to automobile manufacturers. The latter can then mount the encapsulated panes directly in bodywork openings, for example through the use of adhesives.
Through the use of such encapsulated panes, the addition of a finishing seal is avoided. The use of panes of this type enables the number of installation steps and the thus costs for the automobile manufacturer to be reduced. In the interests of simplification, the remainder of the disclosure will relate more specifically to a treatment for the bonding of moulded-on profiles or encapsulating seals.
The encapsulating seals may be of different types. There may be a profile of polyurethane, which is produced by thermoplastic injection moulding or by reaction injection moulding (RIM). It may be a profile produced by thermoplastic injection moulding of other thermoplastic materials, such as a thermoplastic elastomer, in particular olefinic or styrenic elastomers.
The profile may also be a profile of PVC produced by thermoplastic injection moulding; or by the reduced pressure injection moulding of a mixture, having the appropriate viscosity, of a PVC containing a catalyst which is afterwards activated by a high frequency, very high frequency or ultra-high frequency electromagnetic radiation. The latter products are generally termed "plastisols".
The profile or encapsulating seal is most commonly moulded onto the entire periphery of the pane. During the production of this profile, the adhesion between the profile and the glass is not always satisfactory, and can decrease over the course of time.
When the bonding of the pane onto the bodywork opening is achieved by deposition of an adhesive cord onto the pane itself in the area bordering the moulded-on profile, then the profile fulfills only a sealing and aesthetic function. In contrast, however, when the adhesive cord is deposited onto the moulded-on profile, the connection between the pane and the bodywork opening requires the bond between the pane and the moulded-on profile to be very strong and durable, as this bond becomes an important part of the structure itself. Furthermore, the bonds between the profile and the glass have, in the past, not been adequate for ensuring complete leaktightness. For these reasons, attempts have been made to improve the adhesion between the pane and the moulded-on profile.
In one such process, panes are coated with an adhesion agent or primer solution, which enables a stronger bond to be created between the glass and the plastic material. A technique of this type is already in use, notably in the automobile industry. The technique consists of two steps. In the first step, a silane layer is deposited in such a way as to create a link with the glass, then in a second step a primer solution is deposited. It is then possible to produce the moulded-on profile according to one of the techniques listed above. It has been observed, however, that in order to obtain good adhesion, it is necessary to apply the moulded-on profile during the first few hours following coating with the primer solution.
In the case where the manufacturer stores the coated panes for a considerable period of time before the application of the moulded-on profile, acceptable adhesion is obtained only if the primer is reactivated. This therefore necessitates a supplementary step before proceeding with the production of the moulded-on profile.
Of course, the panes could be silane treated and then stored prior to coating with the primer solution. With this procedure, however, it is still necessary to proceed with a preliminary step just before the manufacture of the moulded-on profile. This process has not previously been used.